Crystallisation of table salt is a traditional method for production of almost pure sodium chloride salt. Usually a brine is made from underground salt mines (solution mining) and evaporated to saturation of sodium chloride with subsequent crystallisation. Other minerals in the brine are purged out of the system. Because of increased emphasis on lower sodium diets, several methods have been developed for production of low sodium salts mostly by substituting sodium with potassium chloride and magnesium salts.
Salt consumption is generally considered too high, in the Western world in particular. Salt is used as preservative and taste enhancer, especially in processed food. A high salt intake (i.e. intake of sodium chloride) can increase risk of hypertension, circulation disorders and have other negative effects on health. Further, when excess salt is secreted this causes a burden on the kidneys and increased secretion of other essential minor trace mineral, which can lead to a lack of such minerals. Accordingly, a reduced consumption of salt is desirable.
WO 86/05954 describes a mineral salt composition produced by controlled evaporation of sea water, fractionated precipitation of sodium chloride and recovering the remaining dissolved mineral salts from the mother lye, e.g. by spray drying. The disclosure focuses on the importance of trace minerals but does not discuss how to prevent bitter taste of other components than sodium chloride.
In WO 90/00522 a method is disclosed for production of sodium reduced salt, wherein the sodium chloride is wholly or partly replaced by double salt of potassium compounds and magnesium compounds. The salt is obtained by evaporation of a solution of the salts to dry solids.
WO 92/16117 describes a method for producing a salt mixture of sodium chloride, potassium chloride, magnesium and trace salts by spray drying.
In WO 93/18668 a production of a mixed salt by instant drying is described.
U.S. Pat. No. 7,621,968 describes a step-wise process for producing a low-sodium salt where a first amount of natural seawater is exposed to sunlight such that an amount of the water is evaporated and an amount of sodium chloride is crystallised. A second amount of seawater is added to the remaining brine and from this diluted brine, salt is crystallised having a sodium chloride content of no more than 70 wt %.
WO9318668 discloses a salt product comprising particles of NaCl, K/Mg-double salts and optionally KCl homogeneously distributed throughout each particle and having a molar ratio of K to Mg equal to or greater than one. This method is based on instantaneous drying of a salt slurry having the desired composition, using drum drying as the preferred method.
A problem with many low-sodium salt and raw sea salt products is a bitter taste, because of magnesium and calcium compounds.
Sea salt is in fact not a clear term in the art as it both refers to salt obtained by fully evaporating sea water, leaving as solid residue all the salts from sea water, and also sodium chloride salt obtained from sea water, but not including the other residual salts. The benefits of providing all salt components from seawater is that thus nutritionally beneficial minerals are provided including beneficial trace minerals. However, as mentioned, products obtained by full evaporation of sea water have an unpleasant taste, not readily interchangeable with table salt.
Further commercially useful methods would be much appreciated, for providing low-sodium salt with a nutritionally beneficial salt profile and good organoleptic properties.